With few exceptions, the conventional types of mass flowmeters known as the convective inertia force flowmeter or the Coriolis force flowmeter employ a single or a pair of vibrating conduits which are flexurally vibrated by an electromagnetic vibrator disposed at the center section thereof, and determine the mass flow rate of media moving through the conduit or conduits as a function of a phase angle difference between two alternating electrical signals respectively provided by two vibration sensors detecting the flexural vibration of the conduit at two different sections thereof, respectively. As the conduit providing the flow passage for the media has to be flexurally vibrated in the conventional types of the inertia force flowmeters, the construction and operation of these types of the mass flowmeters become prohibitively expensive and ungainly cumbersome when the flowmeters of large port sizes, e.g., greater than 2 inches, are required. As the costs of even small size inertia force flowmeters of the conventional types are unreasonably high, there is a strong demand for a new generation inertia force flowmeter technology that provides inexpensive and compact inertia force flowmeters of all sizes.